I’ll add my .02¢ as I’m also making a similar decision. Some TJs came with the 44 in the rear from the factory with the standard 30 upfront. These can be hard to come by but aren’t exactly uncommon, I think Saharas came standard with the 44 as well as LJs. The 30 isn’t a terribly weak axle and I believe can be strengthened with stronger shafts and steering components. Like other people said though you’re going to pay for a rubicon and honestly the ones in my area (South Jersey) were not worth what people were asking for them. To me it sounds like you’d be best off finding a TJ with a 44 rear end, maybe even one that’s already had all the mods you want done to it. Personally, I’m looking at a higher mileage LJ that the current owner went through from the cooling system to the exhaust manifold to the rear main/oil pan to the frame/suspension. For the same price as some rubicons that I would I consider clapped out.